1. Field of the Invention
The present invention relates to a test device for electronic devices. Particularly, the present invention relates to a test device for wireless electronic devices.
2. Description of the Prior Art
In the design process of wireless electronic devices, it requires continuously measuring the receiving and transmission status of wireless signals of wireless electronic devices for adjustment and design of wireless electronic devices in the future. In addition, wireless electronic devices still need to be continuously tested before shipping out to ensure the performance of wireless electronic devices satisfying requirements of manufacturers and regulations of authorities.
In order to isolate a wireless electronic device from ambient wireless signal, when the wireless electronic device is tested, the wireless electronic device is usually disposed in the shielding box with metal casing. FIG. 1 illustrates a schematic view of the inner part of a traditional shielding box 10. The traditional shielding box 10 includes a metal casing 11, a wave-absorbing material 20, and a first measurement antenna 30, wherein a feed-in portion 12 is disposed at one end of the first measurement antenna 30, so that the first measurement antenna 30 can receive signals through the feed-in portion 12 and produce electromagnetic field in the shielding box 10.
As shown in FIG. 1, the wave-absorbing material 20 is disposed on an inner surface of the metal casing 11 for absorbing the wireless signal transmitted from a wireless electronic device under test 50 to the metal casing 11. As such, the wave-absorbing material 20 may prevent a plurality of wireless signals from forming a composite wireless signal with a larger power through reflections and refractions to affect the test results. In addition, the metal casing 11 is connected to the ground 60 to avoid the formation of induction loop and guides the ambient wireless signal to the ground 60.
Besides, the first measurement antenna 30 shown in FIG. 1 is substantially a cone extending from one end of the metal casing 11 to the other end thereof. The wireless electronic device 50 is disposed in the metal casing 11 on a plane adjacent to the first measurement antenna 30 for testing. In other words, the first measurement antenna 30 laterally forms an electromagnetic field to cover and test the wireless electronic device 50. However, because the cone has an irregular shape, the first measurement antenna 30 will produce an electromagnetic field having irregular magnitude in the traditional shielding box 10. As such, when the position of the wireless electronic device 50 in the shielding box is changed, the first measurement antenna 30 will receive a significant difference in test result (for example, the emitting power). In other words, the first measurement antenna 30 will obtain unstable measurement results of wireless signal because the wireless electronic device under test 50 is placed at a different position or has a different size.